WPGraphQL support for Co-Authors Plus Plugin

Hey @kirtiraj, you need to register a custom connection that will add the ‘authors’ field to the Post object in GraphQL. In the resolve callback you would just pass the result of the get_coauthors function to the resolver query, which is essentially a WP_User_Query.

add_action( 'graphql_register_types', 'register_authors_connection' );

function register_authors_connection() {
    if ( function_exists( 'get_coauthors' ) ) {
        register_graphql_connection(
            [
		'fromType'           => 'Post',
		'toType'             => 'User',
		'fromFieldName'      => 'authors',
		'connectionTypeName' => 'AuthorsToPostConnection',
		'resolve'            => function ( Post $source, $args, $context, $info ) {
			$resolver = new UserConnectionResolver( $source, $args, $context, $info );
			$coauthor_ids = array_map(
                            function( $coauthor ) {
                                return $coauthor->ID;
                            },
                            get_coauthors( $source->postId )
                        );

			$resolver->set_query_arg( 'include', $coauthor_ids );
			return $resolver->get_connection();
                },
            ]
        );
    }
}